[Mimedefang] Testing HELO

[Les Mikesell]

On Tue, 2003-10-14 at 08:26, Joseph Brennan wrote:
> I'm testing that when a host says HELO with an IP, that the IP is
> actually that host's IP.
> 
> Most of what this gets is spam, as I expected.  But amazingly,
> some legit hosts HELO with an IP that is not their own.  Or
> not so amazingly maybe.
> 

Not amazing.
There is not a 1 to 1 correspondence between hosts and IP numbers
and I'm pretty sure sendmail does not go out if it's way to
care about which interface it is using for each connection.
Also these days it is pretty common to park hosts behind a NAT
so their own concept of IP numbers won't match what you see.

---
  Les Mikesell
   les at futuresource.com